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# String.LocalizationValue.Placeholder

An enumeration of types that can appear as a placeholder in a string interpolation.

```
enum Placeholder
```

## Overview

Foundation uses this type when you create a string with the `\(placeholder: type)` syntax and supply an array of replacement values in a `String.LocalizationOptions`. Placeholders work with [`String`](/documentation/Swift/String) initializers that take an `options:` parameter:

- [`init(localized:options:table:bundle:locale:comment:)`](/documentation/Swift/String/init(localized:options:table:bundle:locale:comment:))
- [`init(localized:options:)`](/documentation/Swift/String/init(localized:options:))
- [`init(localized:defaultValue:options:table:bundle:locale:comment:)`](/documentation/Swift/String/init(localized:defaultValue:options:table:bundle:locale:comment:))

You only use this type directly when specifying one of its enumeration cases in the placeholder syntax, like `\(placeholder: .int)`.

## Topics

### Placeholder types

[`case int`](/documentation/Swift/String/LocalizationValue/Placeholder/int)

The signed integer type, as used for replacement values with the localized string placeholder syntax.

[`case uint`](/documentation/Swift/String/LocalizationValue/Placeholder/uint)

The unsigned integer type, as used for replacement values with the localized string placeholder syntax.

[`case float`](/documentation/Swift/String/LocalizationValue/Placeholder/float)

The single-precision floating-point type, as used for replacement values with the localized string placeholder syntax.

[`case double`](/documentation/Swift/String/LocalizationValue/Placeholder/double)

The double-precision floating-point type, as used for replacement values with the localized string placeholder syntax.

[`case object`](/documentation/Swift/String/LocalizationValue/Placeholder/object)

The object type, as used for replacement values with the localized string placeholder syntax.

### Encoding and decoding

### Hashing

### Comparing placeholder instances

## Relationships

### Conforms To

[`Sendable`](/documentation/Swift/Sendable)

[`Encodable`](/documentation/Swift/Encodable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Decodable`](/documentation/Swift/Decodable)

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

---

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